The Crucian Carp, Carrasius carrasius, is a common river fish that can be found all day, year-round. It sells for 120 Bells, being tied for second-most inexpensive fish alongside Bluegill, losing only to the Tadpole.

An information board in the aquarium will provide information about this fish.

"Crucian carp are fairly easy fish for beginners to catch, but they're also popular with veteran anglers. They are related to koi and can live up to 15 years, making them a great fish to keep in a pond. Male offspring are seldom born, so females significantly outnumber males, making populations suffer. Luckily, females reproduce with males of some other species, so the problem is relatively temporary."

The Crucian Carp is a European fish native to England, but introduced in many different places, as far north as the Arctic circle in the Scandinavian countries, to the southern extremities of central France and the Black Sea. These fish are typically 15cm and weighing at most 1.5kg (3.3lbs). They vary in shape depending on the environment, such as where predatory fish lurk, morphing the carp from a sleeker to a deeper bodied form, into almost a perfect disc shape with well-rounded fins, making them harder to swallow. The Crucian Carp is related to the Goldfish, and is often cross-bred with them.